Electrical device



p '1 1943. M. H. ENGLISH EAL 2,329,343

ELECTRICAL DEVICE Filed March 11, 1942 Ad /r10 HEzagliJ/z RolandRdYydmvsmons ATTORNEY Patented Sept. 14, 1943 2 329 343? UNITED STATES PATENTOFFICE.

ELECTRICAL DEVICE Myrle Hardt English, Pomptcn Lakes, N. .L, and RolandRoswell Nydegger, Wilmington, Del.,

. assignors to E. I. du Pontde Nemours & Company, Wilmington, DeL, acorporation of Delaware 7 Application March 11, 1942, Serial No. 434,268

4 Claims. (Cl. 219-40) The present invention relates to the art of Ingreater detail, the metal strip I of Figure 1 electrical devices, and inparticular to means for is folded about the filament 2 as shown inFigure attaching filaments in conducting relationship 2. This unit iswelded to leading wire 3 using therein. welding tips 4 and 5 as shown inFigure 3, to give This application is a continuation-in-part of thecompleted welded juncture as shown in Figour co-pending applicationSerial No. 303,570, ure 4. In Figure 5 the weld has been completed filedNovember 9, 1939, now U. S. Patent No. without folding the strip I aboutfilament 2, the

issued April 4, 1942. latter being merely sandwiched between the stripDimculties have been encountered in the elec- I and conductor 3. tricalarts in the joining of fine filaments to It is to be noted that thestrip may be comlarger conductors, as in lamp manufacture and posed of adifferent metal from that of either the like, largely clue to thefrangibility of the the filament or the leading wire. For instance,filament. with a copper leading wire an iron strip could be The objectof our invention is an improved used. method for securing togethertightly both in a While we have described our invention parmechanicaland an electrical sense, a fine conticularly with reference tothejoining of a lamp ducting filament and a larger conductingelefilament to a leading wire, it should be underment. A further objectis the attachment of stood that it is applicable as well to anyprobmetallic lamp filaments to their supports or lead lem wherein asmall diameter high resistance wire wires. Additional objects will benoted in the is to be joined to another conductor, whether a following:lamp is involved, or a radio apparatus or any We have found that theforegoing objects are other electrical device. accomplished byelectrically welding the filament The welding apparatus employed may bea conto the other conductor by including in the weld in ventional,mechanical spot-welding unit. The addition to the conductors to bejoined a separate current regulation may he obtained with a con anddistinct metal conducting unit such as a ventional solenoid dash-pottype of timer which small strip of metal sheeting. The metal strip givesonly approximately similar welding cycles. may be wrapped around thefilament and the This is important only in so far as it indicates wholeelectrically welded to the other conductor, that the welding cycle isnot a critical one as in or alternatively the filament may be sandwichedmost fine wire welding. t should be understood between the strip and theother conductor and therefore that the success of the weld of ourinwelded. vention lies in its own structure and need not be Theinvention may be carried out as follows associated in any way withspecific types of weldwith respect to joining a filament to a leadinging equip wire: the leading wire is cleaned and placed in a The methodis advantageous because it can welding jig. The metal strip of tin-ironsheeting be adapted readily to mass production and meinch wide is foldedabout the filament. The chanical assembly operations, and for theimstrip with filament folded within it is then placed proved weld. Theweld is characterized by inon the leading wire and held down with aneleccreased electrical and mechanical durability and trio welding tip.An ordinary welding current resistance to corrosion. is passed throughthe whole, securing together It is to be understood that while we havedethe elements to form a welded juncture which scribed our invention inthe foregoing in detail, includes the post, the wire and the strip ofmetal in conneption with a specific embodiment thereof, sheeting. we donot intend to be limited thereto. Our in- Our invention may beunderstood more readily vention includes within its scope any variationby referring to the accompanying drawing, which thereof which wouldsuggest itself to a skilled sets forth preferred embodiments of thesame. artisan. For instance, we have described in de- Similar numeralsrefer to corresponding parts tail only copper-iron sandwiches; yet anymetalthl'ollghollt t e several figures thereof. conducting sandwich maybe employed. We in- Figllre 1 is a View Of the parts to be Weldedtend tobe limited therefore only by the following Figure 2 is a view of themetal strip folded about patent claims the filament. Figure 3 is a viewof the assembly W 1 i about to be welded. Figure 4 is a view of the 1,Th th of securing a metal m t Completed j tu l e 5 is a View Of a 5having a diameter of the order of magnitude of slightly different weld.a lamp filament to a larger metal conductor which comprises electricallywelding together the filament, the conductor and a separate metalsheeting unit by disposing the filament between the conductor and aportion of the metal sheeting, placing said elements in contact witheach other and passing an electric current serially through them.

2. The method of securing a metal filament having a diameter of theorder of magnitude of a lamp filament to a larger metal conductor whichcomprises electrically forming a weld including the filament, theconductor and a unit of metal sheeting by disposing the filament betweenthe conductor and a portion of the metal sheeting, placing said elementsin contact with each other and passing an electric current seriallythrough them.

3. The method of securing a metal filament having a diameter of theorder of magnitude of a lamp filament to a larger metal conductor whichcomprises folding a strip of metal sheeting about the filament andelectrically welding the whole to the conductor by passing an electriccurrent serially through said elements placed in contact with eachoth'er.

4. In an electrical device. a connection between a metal filament havinga diameter of the order of magnitude of a lamp filament and a largermetal conductor comprising an electrically welded juncture including thefilament, the conductor and a unit of metal sheeting the filament beingdisposed between the conductor and a portion of the metal sheathing.

MYRLE HARDT ENGLISH. ROLAND ROSWELL NYDEGGER.

CERTIFICATE OF CORRECTION. Patent No. 2,529,515. September it, 19%.

MYRLE HARDT ENGLISH, ET AL.

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as follows: Page 2,second column, line 15, claim )4, for "sheathing" read -sheeting-; andthat the said Letters Patent should be read with this correction thereinthat the same may conform to the record of the case in the PatentOffice.

Signed and sealed this 9th day of November, A. D. 19%.

Henry Van Arsdale, (Seal) Acting Commissioner of Patents.

CERTIFICATE OF CORRECTION. Patent No. 2,529,515. September 1h, 19%.

MYRLE HARDT ENGLISH, ET AL.

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as follows: Page 2,second column, line 15, claim 14., for "sheathing" read -sheeting; andthat the said Letters Patent should be read with this correction thereinthat the same may conformto the record of the case in the Patent Office.

Signed and sealed this 9th day of November, A. D. 19h}.

Henry Van Arsdale, (Seal) Acting Commissioner of Patents.

